Jargon is the specialized terminology associated with a particular field or area of activity. Jargon is normally employed in a particular communicative context and may not be well understood outside that context. The context is usually a particular occupation (that is, a certain trade, profession, vernacular or academic field), but any ingroup can have jargon. The main trait that distinguishes jargon from the rest of a language is special vocabulary—including some words specific to it and often different senses or meanings of words, that outgroups would tend to take in another sense—therefore misunderstanding that communication attempt. Jargon is sometimes understood as a form of technical slang and then distinguished from the official terminology used in a particular field of activity.

The terms jargon, slang, and argot are not consistently differentiated in the literature; different authors interpret these concepts in varying ways. According to one definition, jargon differs from slang in being secretive in nature; according to another understanding, it is specifically associated with professional and technical circles. Some sources, however, treat these terms as synonymous. In Russian linguistics, jargon is classified as an expressive form of language, while secret languages are referred to as argots. The use of jargon became more popular around the sixteenth century attracting persons from different career paths. This led to there being printed copies available on the various forms of jargon.